--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Resources/Orthanc/Core/MultiThreading/RunnableWorkersPool.cpp	Fri Mar 23 11:04:03 2018 +0100
@@ -0,0 +1,170 @@
+/**
+ * Orthanc - A Lightweight, RESTful DICOM Store
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2018 Osimis S.A., Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * In addition, as a special exception, the copyright holders of this
+ * program give permission to link the code of its release with the
+ * OpenSSL project's "OpenSSL" library (or with modified versions of it
+ * that use the same license as the "OpenSSL" library), and distribute
+ * the linked executables. You must obey the GNU General Public License
+ * in all respects for all of the code used other than "OpenSSL". If you
+ * modify file(s) with this exception, you may extend this exception to
+ * your version of the file(s), but you are not obligated to do so. If
+ * you do not wish to do so, delete this exception statement from your
+ * version. If you delete this exception statement from all source files
+ * in the program, then also delete it here.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#include "../PrecompiledHeaders.h"
+#include "RunnableWorkersPool.h"
+
+#include "SharedMessageQueue.h"
+#include "../OrthancException.h"
+#include "../Logging.h"
+
+namespace Orthanc
+{
+  struct RunnableWorkersPool::PImpl
+  {
+    class Worker
+    {
+    private:
+      const bool&           continue_;
+      SharedMessageQueue&   queue_;
+      boost::thread         thread_;
+ 
+      static void WorkerThread(Worker* that)
+      {
+        while (that->continue_)
+        {
+          try
+          {
+            std::auto_ptr<IDynamicObject>  obj(that->queue_.Dequeue(100));
+            if (obj.get() != NULL)
+            {
+              IRunnableBySteps& runnable = *dynamic_cast<IRunnableBySteps*>(obj.get());
+              
+              bool wishToContinue = runnable.Step();
+              
+              if (wishToContinue)
+              {
+                // The runnable wishes to continue, reinsert it at the beginning of the queue
+                that->queue_.Enqueue(obj.release());
+              }
+            }
+          }
+          catch (OrthancException& e)
+          {
+            LOG(ERROR) << "Exception while handling some runnable object: " << e.What();
+          }
+          catch (std::bad_alloc&)
+          {
+            LOG(ERROR) << "Not enough memory to handle some runnable object";
+          }
+          catch (std::exception& e)
+          {
+            LOG(ERROR) << "std::exception while handling some runnable object: " << e.what();
+          }
+          catch (...)
+          {
+            LOG(ERROR) << "Native exception while handling some runnable object";
+          }
+        }
+      }
+
+    public:
+      Worker(const bool& globalContinue,
+             SharedMessageQueue& queue) : 
+        continue_(globalContinue),
+        queue_(queue)
+      {
+        thread_ = boost::thread(WorkerThread, this);
+      }
+
+      void Join()
+      {
+        if (thread_.joinable())
+        {
+          thread_.join();
+        }
+      }
+    };
+
+
+    bool                  continue_;
+    std::vector<Worker*>  workers_;
+    SharedMessageQueue    queue_;
+  };
+
+
+
+  RunnableWorkersPool::RunnableWorkersPool(size_t countWorkers) : pimpl_(new PImpl)
+  {
+    pimpl_->continue_ = true;
+
+    if (countWorkers == 0)
+    {
+      throw OrthancException(ErrorCode_ParameterOutOfRange);
+    }
+
+    pimpl_->workers_.resize(countWorkers);
+
+    for (size_t i = 0; i < countWorkers; i++)
+    {
+      pimpl_->workers_[i] = new PImpl::Worker(pimpl_->continue_, pimpl_->queue_);
+    }
+  }
+
+
+  void RunnableWorkersPool::Stop()
+  {
+    if (pimpl_->continue_)
+    {
+      pimpl_->continue_ = false;
+
+      for (size_t i = 0; i < pimpl_->workers_.size(); i++)
+      {
+        PImpl::Worker* worker = pimpl_->workers_[i];
+
+        if (worker != NULL)
+        {
+          worker->Join();
+          delete worker;
+        }
+      }
+    }
+  }
+
+
+  RunnableWorkersPool::~RunnableWorkersPool()
+  {
+    Stop();
+  }
+
+
+  void RunnableWorkersPool::Add(IRunnableBySteps* runnable)
+  {
+    if (!pimpl_->continue_)
+    {
+      throw OrthancException(ErrorCode_BadSequenceOfCalls);
+    }
+
+    pimpl_->queue_.Enqueue(runnable);
+  }
+}